This application relates to a system for pivoting a plurality of variable stator vanes, such as in a gas turbine engine for example.
A gas turbine engine typically includes a fan section, a compressor section, a combustor section, and a turbine section. Air entering the compressor section is compressed and delivered into the combustion section where it is mixed with fuel and ignited to generate a high-speed exhaust gas flow. The high-speed exhaust gas flow expands through the turbine section to drive the compressor and the fan section.
In general, the compressor and turbine section include circumferentially spaced vanes forming vane stages that are axially separated from adjacent vane stages by rotor blades. Some gas turbine engines include variable vanes that pivot about an axis to vary an angle of the vane to optimize engine performance. The variable vanes are mechanically connected to a synchronization ring by a vane arm to drive the variable vane to pivot as the synchronization ring is rotated. The synchronization ring is rotated by crank shaft that is mechanically connected to the synchronization ring. As the synchronization ring is rotated in a circumferential direction around the engine, the relative angle of variable vanes at each stage is varied in order to modify the amount of airflow through the engine.
Linear actuators are known in the art to rotate the crank shaft but generally require several additional moving parts to convert linear motion to rotary motion, with each of the moving parts contributing to vane position error. Engine stability and fuel consumption is related to the accuracy of positioning the angle of the vanes.